Vacuum mixing device with operating element, pressure pump, and vacuum pump for mixing polymethylmethacrylate bone cement

ABSTRACT

A vacuum mixing device or system mixes polymethylmethacrylate bone cement from a monomer liquid and a cement powder. The device or system comprising at least one cartridge comprising an evacuable interior for mixing of the bone cement, a mixing device for mixing the content in the interior of the at least one cartridge, a receptacle for receiving a separate container containing the monomer liquid or comprising an integrated container containing the monomer liquid, an opening device, which is arranged in the region of the receptacle in a manner movable relative to the receptacle so that, by moving the opening device, a separate container arranged in the receptacle is openable by means of the opening device, or the opening device is arranged in the region of the integrated container in a manner movable relative to the integrated container so that, by moving the opening device, the integrated container is openable by means of the opening device, a vacuum pump, in which a movable vacuum plunger for generating a negative pressure is arranged and delimits a vacuum pump chamber of the vacuum pump, a pressure pump, in which a movable pump plunger for conveying a liquid is arranged and delimits a pressure pump chamber of the pressure pump, a connection line, and a fluid connection. The device or system further comprises an operating element that is operatable from outside, wherein, by means of the operating element, the vacuum plunger in the vacuum pump is movable manually, the pump plunger in the pressure pump is movable manually, the opening device is movable manually relative to the receptacle or relative to the integrated container, and the mixing device is movable manually in the interior of the cartridge.

This application claims foreign priority benefit under 35 U.S.C. 119 ofGerman Application No. DE 10 2015 121 277.3 filed Dec. 7, 2015.

FIELD OF THE DISCLOSURE

The invention relates to a vacuum mixing device for the mixing ofpolymethylmethacrylate bone cement (PMMA bone cement) from two startingcomponents, in particular for the mixing of a medical bone cement, andfor storage of the starting components. The invention further relates toa method for the mixing of polymethylmethacrylate bone cement.

Accordingly, the subject matter of the invention is a vacuum mixingdevice for the storage, mixing, and, if applicable, dispensing ofpolymethylmethacrylate bone cement. The invention further relates to amethod for the transferring of monomer liquid into the vacuum mixingdevice and to a method for the mixing of the components ofpolymethylmethacrylate bone cement under vacuum or at negative pressure.

BACKGROUND

Polymethylmethacrylate (PMMA) bone cements are based on the pioneeringwork of Sir Charnley. PMMA bone cements consist of a liquid monomercomponent and a powder component. The monomer component generallycontains the monomer, methylmethacrylate, and an activator(N,N-dimethyl-p-toluidine) dissolved therein. The powder component,which is also referred to as bone cement powder, comprises one or morepolymers, which are produced on the basis of methylmethacrylate andcomonomers, such as styrene, methylacrylate or similar monomers by meansof polymerisation, preferably by suspension polymerisation. The bonecement powder additionally comprises a radiopaquer and the initiatordibenzoylperoxide. During the mixing of powder component and monomercomponent, swelling of the polymers of the powder component in themethylmethacrylate generates a dough that can be shaped plastically andis the actual bone cement. During the mixing of powder component andmonomer component, the activator, N,N-dimethyl-p-toluidine, reacts withdibenzoylperoxide while forming radicals. The radicals thus formedtrigger the radical polymerisation of the methylmethacrylate. Uponadvancing polymerisation of the methylmethacrylate, the viscosity of thecement dough increases until the cement dough solidifies.

Methylmethacrylate is the monomer used most commonly inpolymethylmethacrylate bone cements. Redox initiator systems usuallyconsist of peroxides, accelerators and, if applicable, suitable reducingagents. Radicals are formed only if all ingredients of the redoxinitiator systems interact. For this reason, the ingredients of theredox initiator system in the separate starting components are arrangedappropriately such that these cannot trigger a radical polymerisation.The starting components are stable during storage provided theircomposition is adequate. Only when the two starting components are mixedto produce a cement dough do the ingredients of the redox initiatorsystem, previously stored separately in the two pastes, liquids orpowders, react with each other, forming radicals which trigger theradical polymerisation of the at least one monomer. The radicalpolymerisation then leads to the formation of polymers while consumingthe monomer, as a result of which the cement dough is cured.

PMMA bone cements can be mixed by mixing the cement powder and themonomer liquid in suitable mixing beakers with the aid of spatulas. Onedisadvantage of said procedure is that air inclusions may be present inthe cement dough thus formed and can cause destabilisation of the bonecement later on.

For this reason, it is preferred to mix bone cement powder and monomerliquid in mixing devices with vacuum sources, since mixing in a vacuumremoves air inclusions from the cement dough to a large extent and thusachieves optimal cement quality. Bone cements mixed in a vacuum or atnegative pressure have clearly reduced porosity and thus show improvedmechanical properties. A large number of vacuum cementing systems havebeen disclosed of which the following shall be listed for exemplarypurposes: U.S. Pat. Nos. 6,033,105 A, 5,624,184 A, 4,671,263 A,4,973,168 A, 5,100,241 A, WO 99/67015 A1, EP 1 020 167 A2, U.S. Pat. No.5,586,821 A, EP 1 016 452 A2, DE 36 40 279 A1, WO 94/26403 A1, WO00/35506 A1, EP 1 005 901 A2, U.S. Pat. No. 5,344,232 A. In the vacuumcementing systems thus specified, there is a need to connect an externalvacuum pump to generate the negative pressure. These are generallyoperated by compressed air utilising the Venturi principle. Thecompressed air required for operation of the vacuum pumps is suppliedeither by stationary compressed air facilities or byelectrically-operated compressors. In addition, it is also feasible touse electrically-operated vacuum pumps to generate vacuum.

Cementing systems in which both the cement powder and the monomer liquidare already packed in separate compartments of the mixing systems andare mixed with each other in the cementing system only right beforeapplication of the cement, are a development of cementing technology.Such full-prepacked mixing systems were proposed through EP 0 692 229A1, DE 10 2009 031 178 B3, U.S. Pat. Nos. 5,997,544 A, 6,709,149 B1, DE698 12 726 T2 and U.S. Pat. No. 5,588,745 A. Said mixing systems alsorequire an external vacuum source. In this context, the patent DE 102009 031 178 B3 discloses a vacuum mixing device having a two-partdispensing plunger that can also be used for a vacuum mixing deviceaccording to the invention. Here, a combination of a gas-permeablesterilisation plunger and a gas-impermeable sealing plunger is used.

If vacuum mixing devices are used for cementing, external vacuum pumpsneed to be provided. Said vacuum pumps are expensive and need to becleaned after use.

Moreover, vacuum hoses for connecting the vacuum pumps to the vacuummixing devices are required. Said vacuum hoses need to be enclosed withthe vacuum mixing devices. Accordingly, prior to the mixing using avacuum mixing device, the vacuum pump needs first to be set up in theoperating theatre (OP theatre) and must be connected to an energysource, such as compressed air, or to an electrical power source. Then,the vacuum pump is connected to the vacuum mixing device by means of avacuum hose. Said installation steps take up costly OP time and arepotentially error-prone. The vacuum pump and connecting lines to thevacuum mixing device and to external energy sources and supply linestake up space and constitute potential tripping hazards and obstaclesthat can disturb the often hectic procedure during surgery.

A further interesting concept has been proposed through EP 1 886 647 A1.Here, the cement powder is stored in an evacuated cartridge and themonomer liquid is situated in a separate container. The cartridge, whichis kept at a negative pressure, being opened causes the monomer liquidto be aspirated into the cartridge without any ingress of air. A bonecement dough free of air inclusions is thus produced. Said conceptrequires the cartridge to remain closed in vacuum-tight manner duringthe storage before use such that no non-sterile air can enter into thecartridge. For this purpose, the cartridge must be sealed in a stablehermetic manner. Accordingly, one associated disadvantage is that thedesign is quite elaborate and that the content in the cartridge cannotbe mixed by an externally-operated mixing system after aspiration of themonomer since a feedthrough for a mixing bar or for a mixing tube wouldnot readily be permanently vacuum-tight.

SUMMARY OF THE DISCLOSURE

Accordingly, it is the object of the invention to overcome thedisadvantages of the prior art. Specifically, the disadvantages of theknown vacuum mixing devices as full-prepacked systems having an externalvacuum source are to be overcome without having to maintain a negativepressure over a long period of time. It is the object of the invention,specifically, to develop a vacuum mixing device in which a negativepressure is generated only just before the cement components are beingmixed. The device is to be simplified to the greatest possible extentand is to allow a negative pressure with respect to the surroundingatmosphere to be generated, at least once, in a cement cartridge.Moreover, it can be advantageous that the vacuum mixing device iscapable of enabling a transfer of monomer liquid from a monomercontainer into a cartridge filled with cement powder. Moreover, a methodis then to be provided that enables a monomer transfer and a vacuummixing in full-prepacked mixing devices. Moreover, it is to be possibleto manufacture the vacuum mixing device to be developed mainly frominexpensive plastics material.

A further object of the invention is to develop a simple, closedprepacked mixing device with which polymethylmethacrylate bone cementpowder and monomer liquid can be stored in separate compartments, andthen mixed. It is to be possible to transfer the monomer liquid into thecement powder just before the mixing of the components, without use ofexternal vacuum sources, external electric drives and externalcompressed air drives. With the prepacked mixing device it will bepossible to produce polymethylmethacrylate bone cement purely by manualactuation, independently of additional external devices. Here, themanual actuation is to be simplified to the greatest possible extent.The opening of the monomer ampoule, or monomer ampoules, the monomertransfer, the generation of a vacuum or a negative pressure, and themixing of the cement components is to be caused preferably by a simplemovement, where possible, which has to be repeated particularlypreferably only a few times, for example 3 to 5 times. The use of thevacuum mixing device for the user is thus to be simplified to thegreatest possible extent, such that costly training can be limited orspared. Furthermore, operation of the vacuum mixing device simplified tothe greatest possible extent is intended to minimize potential operatingerrors, thus increasing patient safety.

The polymethylmethacrylate bone cement powder can be combined and mixedwith the monomer liquid within the vacuum mixing device by the medicaluser, without both cement components coming into contact with themedical user. Contact between the medical user and thepolymethylmethacrylate bone cement powder and the monomer liquid must beruled out. The vacuum mixing device to be developed is a full-prepackedvacuum mixing device. The vacuum mixing device is to be designed so thatthe monomer liquid is transferred into the polymethylmethacrylate bonecement powder by vacuum without the use of external vacuum pumps.Furthermore, the vacuum mixing device is to ensure the production ofbone cement dough in a functional and reliable manner without externalenergy sources, such as compressed air, vacuum or electrical current,even under the simplest external conditions. The vacuum mixing device isalso intended particularly preferably to do without an internal energystore, such as batteries or also mechanical energy stores, to thegreatest possible extent. The vacuum mixing device is intended to beusable autonomously, without additional technical equipment.

Moreover, a device that is inexpensive to manufacture and that worksreliably for the mixing of a medical cement and, if applicable, forstorage of the starting components, and a method for the mixing of thebone cement is to be devised, in which the simplest possible manualoperation can be used to mix the starting components, if possiblewithout air inclusions arising in the mixing material.

The main component of the polymethylmethacrylate bone cement, as mixingmaterial, shall be a powder and the second component shall be present inthe form of a liquid. Preferably, it shall be possible to store the twostarting components of the bone cement separately from each other in thevacuum mixing device and to combine them safely through the use of thedevice.

The objects of the invention are achieved by a vacuum mixing device forthe mixing of polymethylmethacrylate bone cement from a monomer liquidand a cement powder, the vacuum mixing device comprising at least onecartridge having an evacuable interior for mixing of the bone cement, amixing device for mixing the content in the interior of the at least onecartridge, which mixing device is arranged movably in the interior, areceptacle for receiving a separate container containing the monomerliquid or comprising an integrated container containing the monomerliquid, an opening device, which is arranged in the region of thereceptacle in a manner movable relative to the receptacle so that, bymoving the opening device, a separate container arranged in thereceptacle is openable by means of the opening device, or the openingdevice is arranged in the region of the integrated container in a mannermovable relative to the integrated container so that, by moving theopening device, the integrated container is openable by means of theopening device, a vacuum pump, in which a movable vacuum plunger forgenerating a negative pressure is arranged and delimits a vacuum pumpchamber of the vacuum pump, a pressure pump, in which a movable pumpplunger for conveying a liquid is arranged and delimits a pressure pumpchamber of the pressure pump, a connection line, which connects theinterior of the at least one cartridge to the vacuum pump chamber of thevacuum pump, and a fluid connection, which connects the interior of theat least one cartridge to the pressure pump chamber of the pressurepump, wherein the vacuum mixing device comprises an operating elementthat is operatable from outside, wherein the vacuum plunger in thevacuum pump is movable manually by means of the operating element, thepump plunger in the pressure pump is movable manually by means of thesame operating element, the opening device is movable relative to thereceptacle or relative to the integrated container by means of the sameoperating element, and wherein the mixing device in the interior of thecartridge is movable by means of the same operating element in order tomix the content in the interior of the cartridge.

The vacuum mixing device is preferably also suitable for storing thestarting components of the polymethylmethacrylate bone cement. Themonomer liquid and/or the cement powder are particularly preferablycontained in the vacuum mixing device. The starting components of thepolymethylmethacrylate bone cement are the cement powder and the monomerliquid, wherein the monomer liquid is preferably contained in a glassampoule, which is arranged as a separate container in the receptacle.However, the monomer liquid can also be contained in a film bag asseparate container or can be contained in the integrated container,which is formed by the receptacle or the vacuum mixing device itself.

The term “vacuum mixing device” is not to be understood incorrectly inthe sense that a vacuum is mixed with something, but instead in thesense that the starting components of the bone cement, i.e. the monomerliquid and the cement powder, are mixable under vacuum or under apressure lower than ambient pressure (negative pressure).

The term negative pressure always relates in the present case to apressure relative to the surrounding atmosphere, which pressure istherefore lower than the surrounding atmospheric pressure.

On account of the specific requirements, such as the small volume of theinterior of the cartridge, there is no need for more elaborate pumpsystems.

Provision can be made preferably so that the vacuum pump and thepressure pump are integrated in the vacuum mixing device. Provision canalso be made preferably so that the pressure in the interior of the atleast one cartridge can be reduced by at least 50%, preferably can bereduced by at least 90%, by means of the pumping process.

Provision can also be made in accordance with the invention preferablyso that the cement powder is contained in the interior of the cartridge.The cement powder then does not have to be filled into the interior ofthe cartridge.

By coupling the opening device to the operating element, the containerin the receptacle or the integrated container is openable by means ofthe opening device by manually operating the operating element.

In the context of the present invention, the term “evacuable” means thata gas can be removed, i.e. for example a gas can be suctioned from theinterior of the cartridge so that a negative pressure then remains inthe interior of the cartridge. This negative pressure can be used inaddition to the pressure applied by the pressure pump in order to suckin the monomer liquid.

The vacuum mixing device comprises either a receptacle into which aseparate container, such as a glass ampoule or a film bag, whichcontains the monomer liquid can be inserted, or an integrated containerwhich is formed as an integral part of the vacuum mixing device and inwhich the monomer liquid is already contained.

Provision can also be made so that more than one cartridge is provided,each of which has an interior, wherein a mixing device is then providedin each interior and each interior is connected to the vacuum pumpchamber of the vacuum pump, the pressure pump chamber of the pressurepump, or to a corresponding vacuum pump chamber of a plurality ofseparate vacuum pumps and a corresponding pressure pump chamber of aplurality of separate pressure pumps via a connection line.

The receptacle is also preferably suitable and intended for fixing aglass ampoule or the glass ampoule in the receptacle. The glass ampoulefor this purpose clearly must be shaped appropriately. By way ofexample, the glass ampoule can be plugged into the receptacle by meansof a press fit.

Provision can be made in accordance with the invention so that thereceptacle is closed on one side by means of a lid. Here, at least onegas-permeable opening can preferably be provided in the lid, throughwhich opening gas can flow into the receptacle or can flow in once themonomer liquid flows out from the receptacle. This is intended to avoidthe formation of a negative pressure in the receptacle, which negativepressure counteracts the flow of the monomer liquid into the pumpchamber of the pressure pump.

The cartridge preferably has a pressure-tight feedthrough, through whicha bar, a cable or a mixing shaft is passed, by means of which the mixingdevice is movable from outside the cartridge. For this purpose, the bar,the cable, or the mixing shaft is preferably mounted in the feedthroughrotatably and displaceably in the longitudinal direction. The content inthe cartridge can be well mixed by means of the mixing device.

Preferred embodiments can be characterised in that the vacuum mixingdevice has a total weight less than 10 kg, particularly preferably has atotal weight less than 2 kg, particularly preferably less than 1 kg.

These low weights are possible with the structure according to theinvention of the vacuum mixing device with manually operable operatingelement and the vacuum pump. The low weight has the advantage that thevacuum mixing device is portable and transportable and usable withoutconnection to supply lines and without great preparation efforts.

Provision can be made in accordance with the invention so that a sieveand/or a filter are/is arranged below the receptacle, the separatecontainer, or below the integrated container so that the content in theopened integrated container or separate container flows through thesieve and/or the filter.

Glass splinters, film snippets, or other residues of the closure or ofthe separate or integrated container created when the separate orintegrated container is opened by means of the opening device can thusbe held back. A clogging of the fluid connection to the interior of thecartridge and a blocking of the pressure pump and a contamination of thebone cement to be produced is thus prevented.

Vacuum mixing devices according to the invention are characterised inthat they do without an electric drive. Provision can thus be made inaccordance with the invention so that the vacuum mixing device does nothave an electric drive or at least the vacuum pump, the pressure pump,the opening device and the mixing device are not driven by means of anelectric drive. Instead, these component parts are driven in accordancewith the invention via the manually operable operating element. Vacuummixing devices according to the invention can also be constructedwithout electronics or electronic component parts. A vacuum mixingdevice according to the invention can thus also be characterised in thatno electronics are installed therein or no electronics or electroniccomponent parts are used at least in order to drive the vacuum pump, thepressure pump, the opening device, and the mixing device.

Electric motors or compressors therefore are not required in order toconstruct vacuum mixing devices according to the invention.

Furthermore, provision can be made in accordance with the invention sothat the vacuum mixing device does not have any energy stores, inparticular no electrical energy stores, such as a primary battery or arechargeable battery, and no compressed gas store, such as a CO₂compressed gas cartridge, or so that at least no energy stores,preferably no electrical energy stores or compressed gas stores, areused in order to drive the vacuum pump, the opening device, and themixing device. The vacuum mixing device, however, preferably also doesnot have any resilient energy stores, such as tensioned springs.

In the case of vacuum mixing devices according to the invention,provision can be made so that the operating element is connected orconnectable to the vacuum plunger and to the pump plunger in such a waythat the vacuum plunger is movable manually in the vacuum pump and thepump plunger is movable manually in the pressure pump by operation ofthe operating element.

As a result of this, the vacuum plunger and the pump plunger is movable,in particular directly, by means of the operating element. Here,provision can be made so that the vacuum plunger and the pump plungerare connected to the operating element only after a first operation ofthe operating element, in such a way that the vacuum plunger in thevacuum pump is moved by a further operation of the operating element andthe pump plunger in the pressure pump is moved by a further operation ofthe operating element. Here, a lever is particularly well suited for theembodiment of the operating element, which lever can be pulled or pushedor pivoted back and forth about an axis so that the separate containerin the receptacle or the integrated container is opened after a firstmovement of the lever and in so doing the vacuum plunger, the pumpplunger and/or the mixing device are/is connected to the operatingelement in such a way that the vacuum plunger in the vacuum pump, thepump plunger in the pressure pump and/or the mixing device in theinterior of the cartridge are/is moved in the event of a reversemovement of the lever. In addition, large forces can be transferredmanually into the vacuum mixing device without difficulty by means of alever.

Furthermore, provision can be made so that the receptacle, at least inregions, has closed side walls for receiving a glass ampoule as separatecontainer, wherein the receptacle has at least one deformable closedside wall and a supporting element is provided opposite the deformableside wall, wherein the opening device is pressable via the operatingelement against the deformable side wall of the receptacle so that thedeformable side wall deforms in such a way that a matching glass ampoulearranged in the receptacle can be broken open by means of the openingdevice.

As a result of this measure, the receptacle can be largely closedoutwardly. In addition, it can be ensured as a result that a glassampoule can also be opened within the closed receptacle without furthermonomer liquid being able to escape from the vacuum mixing device,whereby the risk of contamination of the surroundings of the vacuummixing device with the content in the cartridge, in particular with themonomer liquid, can be ruled out or the risk of this is at leastsignificantly reduced.

With a development of the present invention it is proposed for theopening device to have a first lever which is mounted rotatably about afirst axis in relation to the receptacle or the integrated container,wherein a free end of the first lever is pushable against a deformableside wall of the receptacle or the integrated container, wherein theoperating element is formed by a second lever which is mounted pivotablyabout a second axis in relation to receptacle or the integratedcontainer, wherein the second axis divides the second lever into a shortlever arm and a long lever arm, wherein an end of the short lever arm isto be pushed by manual operation of the long lever arm against the firstlever so that the free end of the first lever pushes against thedeformable side wall and deforms this in such a way that a separatecontainer disposed in the receptacle is openable, or pushes the free endof the first lever against the integrated container so that theintegrated container opens towards a fluid connection.

Here, provision can be made so that the separate container is a glassampoule which matches the receptacle and which can be broken open by thepressure of the free end of the first lever or is a film bag which isarranged in the receptacle and which can be pierced or slit open or tornopen by the pressure of the free end of the first lever.

Provision can also be made in such embodiments so that an edge isarranged at the free end of the first lever on the side facing towardsthe receptacle. The length ratio of the long lever arm to the shortlever arm is preferably at least 5 to 1. Furthermore, provision can bemade so that the second lever is to be rotated in the same plane as thefirst lever, wherein the movement of the second lever engages in themovement of the first lever. Provision can also be made preferably sothat the second axis of the second lever is arranged above the firstaxis of the first lever, wherein the first axis of the first lever andthe second axis of the second lever are preferably arranged parallel toone another.

With vacuum mixing devices of this type with glass ampoule, it ispossible to break open a glass ampoule over a large area within thedevice or the cementing device, such that the monomer liquid flows outfrom the glass ampoule within a short period of time and is madeavailable for mixing with the medical bone cement powder. With the aidof the two levers, which interact with one another, it is possible todirect the pressure on the glass ampoule in the direction in which theglass ampoule sits in the receptacle so that the glass ampoule cannotescape from the receptacle. At the same time, a very accurately definedlocal pressure can be exerted onto the glass ampoule, by means of whichthe glass ampoule in the vacuum mixing device can be broken open. Withthe aid of the deformable side wall, is possible to ensure that theforce is transferred through this side wall into the interior of thereceptacle and onto the glass ampoule, wherein the receptacle remainsclosed. An escape of the monomer liquid from the receptacle can thus beruled out. With the aid of the sieve and/or the filter, glass splinterspossibly created as the glass ampoule is opened can be held back. Themonomer liquid can then be used for mixing with the bone cement powder.

The particular advantage of the device according to the invention alsolies in the fact that any glass ampoules, regardless of the ampoulelength and the geometry of the ampoule head, can be safely opened whenthe ampoule diameter is equal to or slightly greater than the innerdiameter of the ampoule holder or the receptacle. It is also aparticular advantage that when breaking the ampoule wall in the regionof the ampoule base, the liquid contained in the glass ampouleimmediately flows out completely, independently of the surface tension.By contrast, in the case of conventional ampoule breakers, the liquidflows out through the relatively narrow cross-section of the ampouleneck, after separation of the ampoule head, significantly more slowly.Here, reasonably high outflow speeds are attained only when thecross-section of the ampoule neck is large enough so that the surfacetension of the liquid cannot hold the meniscus of the liquid in theampoule neck.

The receptacle is preferably a hollow cylinder. The receptacle likewisepreferably consists of an elastomer or comprises an insert made of anelastomer, such as an ethylene propylene diene (EPDM) rubber.

Provision can also be made here so that a shoulder for supporting theglass ampoule is arranged in the receptacle, wherein the shoulder issmaller than half the area of the ampoule base or the ampoulecross-section. Here, provision can in turn be made preferably so thatthe shoulder is arranged in the receptacle in such a way that thedistance between the shoulder and a sieve and/or filter arrangedtherebelow is the same size as or greater than the outer diameter of theglass ampoule to be inserted.

With a vacuum mixing device that can be provided particularly easily andeconomically, it is proposed for the operating element to be manuallymovable, preferably to be a lever pivotable about an axis, wherein theoperating element is operatively connected so as to be brought intooperative connection with the opening device, the vacuum pump, thepressure pump, and the mixing device in such a way that with a firstoperation of the operating element a separate container in thereceptacle or the integrated container is to be opened, and with afurther operation of the operating element the vacuum plunger in thevacuum pump is to be driven, the pump plunger in the pressure pump is tobe driven, and the mixing device in the interior is to be driven.

A force which is to be applied manually and which acts on the operatingelement, in particular the lever, can hereby be used in order to firstlyopen the separate or integrated container and then drive or move thevacuum pump, the pressure pump, and the mixing device by means of thesame operating element. Levers as operating elements are particularlywell suited for transferring manual force into the vacuum mixing device.This is also the case because it is possible to increase the usableforce via the length of the lever arm.

Here, provision can be made so that the vacuum plunger of the vacuumpump, the pump plunger of the pressure pump, and/or the mixing deviceare/is to be driven via a flexible cable and/or a rod, wherein a detentmeans is provided on the flexible cable and/or the rod and afterfirst-time operation of the operating element engages with a matingdetent means on the operating element or with a mating detent meansconnected to the operating element so that, with operation of theoperating element subsequent to the latching, the vacuum plunger of thevacuum pump, the pump plunger of the pressure pump and/or the mixingdevice are/is to be driven via the cable and/or the rod by means of theoperating element.

The force can thus be transferred from the operating element to thevacuum plunger, the pump plunger and/or the mixing device. The flexiblecables are particularly well suited for the transfer of force, since thedirection of the force can be deflected therewith without complexmechanics. The flexible cable is preferably sufficiently stiff or rigidso that the vacuum plunger, the pump plunger and/or particularly themixing device can be moved back and forth in both directions. The cablecan be guided and/or supported for this purpose. By way of example, thecable for this purpose can be guided in a channel, or can be supportedand/or deflected at suitable points by a housing and by struts and/ordeflection rollers in the housing. Due to the use of the detent meansand the mating detent means, it is possible to ensure that the separatecontainer in the receptacle or the integrated container is firstlyopened and the monomer liquid runs out completely, before thepressure-vacuum pump or the vacuum plunger of the vacuum pump, the pumpplunger of the pressure pump and/or the mixing device is operated. Byway of example, it is thus possible to prevent the vacuum pump and thepressure pump from being operated before the monomer liquid isavailable.

Is also proposed for the mixing device to be axially movable in theinterior in the longitudinal direction by operation of the operatingelement.

A very comprehensive mixing of the interior is hereby achieved inparticular for a cylindrical interior. At the same time, the mixingdevice can be constructed in a compact manner, since it does not have toextend along the entire length of the interior.

Provision can also be made preferably so that the mixing device isrotatable about the longitudinal axis of the interior by operation ofthe operating element in the interior, wherein preferably for thispurpose a cylinder connected to the mixing device and having an externalthread moves in a stationary sleeve having a matching internal thread sothat, when the cylinder moves along the longitudinal direction withinthe sleeve, a rotation of the cylinder is enforced, wherein the rotationof the cylinder transfers to the mixing device in the interior of thecartridge.

An even more thorough mixing of the content in the interior is achievedhereby. Bone cement clinging to the wall of the interior can also beeffectively mixed as a result. The bone cement is thus mixed morequickly and more effectively.

With a development of the present invention provision can also be madeso that the vacuum pump chamber of the vacuum pump is gas-tight and isarranged in the interior of the vacuum pump, wherein the vacuum plungeris manually drivable via the operating element in at least onedirection, such that the vacuum pump chamber is to be enlarged by themovement of the vacuum plunger and the interior of the at least onecartridge is to be evacuable through the connection line by means of theresultant negative pressure created in the vacuum pump chamber.

A particularly good pumping effect of the vacuum pump is herebyachieved, and therefore the vacuum that can be generated in the interiorof the cartridge is improved. The vacuum plunger with the operatingelement can particularly preferably be moved manually repeatedly in twodirections along the axis of the vacuum pump chamber so that a repeatedpumping in order to evacuate the interior of the cartridge is possible.

Here, provision can be made so that the volume increase of the vacuumpump chamber is at least as large as the free volume of the interior ofthe cartridge, and the volume increase of the vacuum pump chamber ispreferably at least as large as the sum of the volume of the interior ofthe cartridge in which the cement powder of the PMMA bone cement iscontained, and the volume of the connection line, and the volume of afluid connection between the interior of the cartridge and thereceptacle for the separate container or the integrated container, andthe volume of a monomer liquid to be mixed with the cement powder of thePMMA bone cement in the cartridge.

It is thus ensured that the vacuum pump can evacuate the interior of thecartridge with just one stroke or with few strokes of the vacuumplunger. Here, the volume of the vacuum pump chamber prior to thepumping process is ideally as small as possible. Provision can thus bemade preferably so that the volume of the vacuum pump chamber after thepumping process is at least 10 times greater than the volume of thevacuum pump chamber prior to the pumping process, particularlypreferably is at least 20 times greater than the volume of the vacuumpump chamber prior to the pumping process. The vacuum plunger preferablydoes not bear tightly in an areally flush manner against the interior ofthe vacuum pump, in particular the top surface of a hollow cylindercomprising the connector for the connection line, such that the vacuumplunger area is not fixedly sucked against this area such that it canonly be moved with difficulty in order to start the movement. For thispurpose, spacers can be provided on the top surface in the vacuum pumpchamber and/or on the vacuum plunger in the vacuum pump chamber.

Provision can also be made so that the pressure pump chamber of thepressure pump is liquid-tight and is arranged inside the pressure pump,wherein the pump plunger is drivable manually via the operating elementin at least one direction so that the pressure pump chamber is to bemade smaller by the movement of the pump plunger and the monomer liquidis to be pushed from the pressure pump chamber through the fluidconnection into the interior of the at least one cartridge by means ofthe resultant pressure created in the pressure pump chamber.

A particularly good pumping effect of the pressure pump is herebyachieved. The monomer liquid can thus be driven particularly effectivelyfrom the pressure pump chamber into the interior of the cartridge byoperation of the operating element.

In order to be able to operate the vacuum pump with a number ofactuations of the actuating element, or so as to be able to utilise amultiple stroke of the vacuum plunger of the vacuum pump, provision canbe made so that a first one-way valve is arranged in the connection fromthe vacuum pump chamber to the connection line or in the connectionline, which first one-way valve is open or is actively opened when apressure lower than in the interior of the cartridge prevails in thevacuum pump chamber and is in a closed state or is actively closed whena pressure equal to or higher than in the interior of the cartridgeprevails in the vacuum pump chamber, and a second one-way valvepreferably connects the vacuum pump chamber to the surroundings of thevacuum pump, which second one-way valve is open or is actively openedwhen a pressure higher than in the surroundings of the vacuum pumpprevails in the vacuum pump chamber and is in the closed state or isactively closed when a pressure equal to or lower than in thesurroundings of the vacuum pump prevails in the vacuum pump chamber,wherein the one-way valves are preferably check valves.

With the first one-way valve, a flow is possible from the interior ofthe cartridge into the vacuum pump chamber, but flows in the oppositedirection are largely prevented.

As a result of the second one-way valve, an overpressure in the vacuumpump chamber can be relieved via the second one-way valve.

A particularly good vacuum or a particularly good negative pressure inthe interior of the cartridge can be generated hereby with repeatedpumping by multiple movement of the vacuum plunger and can be maintainedor improved further during the mixing process as well.

Furthermore, provision can be made so that the vacuum plunger and thepump plunger are mounted axially movably in a hollow cylinder, whereinthe hollow cylinder is closed on a first side or is closed apart from afeedthrough for a rod or cable connected to the operating element andthe vacuum plunger and pump plunger, in particular is closed by aclosure, wherein a vacuum pump chamber is preferably formed in thehollow cylinder between the vacuum plunger and the first closed side,and a pressure pump chamber is formed in the hollow cylinder between thepump plunger and a closure, wherein the closure of the hollow cylinderis arranged on the side of the hollow cylinder opposite the first side.

The vacuum pump chamber and the vacuum plunger and also the pressurepump chamber and the pump plunger preferably have a cylindricalgeometry. As a result of these measures and also as a result of thecylindrical geometry, a combined pressure-vacuum pump that isparticularly easily and inexpensively manufactured is proposed, which iseasily operated and is particularly unsusceptible to malfunctions.

It is also proposed that the vacuum plunger and/or the pump plungerare/is connected or connectable to the operating element via a rodand/or a cable, and preferably for the vacuum plunger to be moved in thevacuum pump by operation of the operating element and/or for the pumpplunger to be moved in the pressure pump by operation of the operatingelement.

A particularly simple vacuum mixing device is hereby provided, withwhich there is no risk of possible interruptions. The direct connectionof the operating element to the vacuum plunger via the cable and/or therod can be provided with a one-part injection-moulded part made ofplastics material. Alternatively, a transmission or a gearing can alsobe provided, by means of which the force exerted onto the operatingelement is transmitted to the vacuum plunger in order to enable a morepowerful movement of the vacuum plunger.

In a further development of the vacuum mixing device, provision can bemade so that a movable dispensing plunger for dispensing the mixed bonecement from the cartridge is arranged in the interior of the cartridge,wherein the dispensing plunger is preferably releasably locked or can belocked in order to prevent a movement of the dispensing plunger underthe action of the negative pressure.

The operation of the vacuum mixing device is simplified by thedispensing plunger.

Here, provision can be made so that the dispensing plunger has a passagewith a gas-permeable pore plate, which is impermeable for cement powder,wherein the passage with the pore plate connects the interior of thecartridge to the connection line and/or the surroundings in agas-permeable manner, wherein the passage is closable in a gas-tightmanner, preferably is closable in a gas-tight manner by means of asealing plunger of the dispensing plunger.

With the pore plate it is possible to ensure that the interior of thecartridge with the cement powder therein can be sterilised with the aidof a gas, such as ethylene oxide, without there being any risk that thecement powder will pass from the interior of the cartridge externallyinto the surroundings.

Provision can also be made preferably so that the cartridge is a cementcartridge filled with cement powder and a separate container containinga monomer liquid is arranged in the receptacle or a monomer liquid iscontained in the integrated container.

The monomer liquid can thus be transferred from the separate orintegrated container into the interior of the cartridge by means of thesame pumping movement or the same pumping process by means of which theinterior of the cartridge is evacuated. The vacuum or the negativepressure generated manually by the vacuum pump is used here at the sametime to suck the monomer liquid into the cartridge.

Provision can also be made so that the cartridge, the vacuum pump, thepressure pump and all lines and also the receptacle or the integratedcontainer are fixedly and/or releasably connected to a common base partand/or a housing, wherein the vacuum pump, the pressure pump and alllines as well as the receptacle or the separate container are preferablyfixedly connected to the base part and/or the housing, and the cartridgeis releasably connected to the base part and/or the housing.

A vacuum mixing device of this type can be easily placed and can beeasily operated. The use of the vacuum mixing device is thus simplified.Merely a flat substrate for setting up the vacuum mixing device must beprovided at the site of use, which in most OP areas does not pose anyproblems.

In accordance with one embodiment provision can be made so that theseparate container containing the monomer liquid is a film bag which canbe cut open or torn open in the receptacle by means of the openingdevice, or is a glass ampoule which can be broken open in the receptacleby means of the opening device.

Commercially available packaging options for the monomer liquid can thusbe used, without having to open these outside the vacuum mixing device.

It is proposed for the receptacle or the integrated container to beconnected via a funnel to the pressure pump chamber of the pressurepump. The mouth of the funnel in the pressure pump chamber should havethe greatest area possible, but should have a narrow diameter parallelto the movement of the pump plunger so that on the one hand the monomerliquid can flow into the pumping chamber with as little hindrance aspossible and on the other hand the mouth of the funnel in the pumpchamber can be covered by the pump plunger as easily as possible,moreover by means of a short movement, so that the monomer liquid is notpushed back from the pump chamber into the receptacle or the integratedcontainer.

The mouth of the fluid connection into the interior of the cartridge ispreferably arranged on the opposite side of the mouth of the connectionline between the interior and the vacuum pump chamber.

As a result, the monomer liquid can be conveyed via a dedicated line(the fluid connection) into the interior of the cartridge.

With a development of the present invention, it is also proposed for anegative pressure to be generated in the vacuum pump chamber as a resultof the movement of the vacuum plunger in the vacuum pump, wherein a gasis evacuable through the connection line from the interior of the atleast one cartridge by means of the negative pressure.

A particularly simple and unsusceptible design is hereby provided.

Provision can also be made in accordance with the invention so that thevacuum pump and the pressure pump are constructed as a combinedpressure-vacuum pump, the pressure-vacuum pump comprising a hollowcylinder with a gas-tight closure at a first hollow cylinder end and aliquid-tight closure at the opposite second hollow cylinder end, whereinthe hollow cylinder is connected or connectable at the first and at thesecond hollow cylinder end to the interior of the cartridge, the vacuumplunger, which is arranged in the hollow cylinder in a gas-tight andaxially movable manner, and the pump plunger, which is arranged in thehollow cylinder in a liquid-tight and axially movable manner, whereinthe vacuum plunger and the pump plunger in the pressure-vacuum pump aremovable by means of the manually operable operating element, wherein,with a movement of the vacuum plunger by means of the manually operableoperating element, the vacuum plunger is movable axially away from thegas-tight closure and gas can thus be evacuated from the interior of thecartridge, and, when the pump plunger is moved by means of the manuallyoperable operating element, the pump plunger is movable axially towardsthe liquid-tight closure and a monomer liquid can thus be pushed fromthe pump chamber into the interior of the cartridge, wherein theoperating element is operatively connected to the opening device, andwherein the operating element is connected to the mixing device in theinterior of the cartridge in such a way that the mixing device in theinterior of the cartridge is movable with operation of the operatingelement.

This design is particularly simple, and the parts essential for it canbe manufactured from plastics material by injection moulding.

With a particularly preferred embodiment of the present invention,provision can be made so that the vacuum pump, the pressure pump, theopening device, and the mixing device are drivable via the movement ofthe operating element, wherein the operating element is preferably movedby the action of manual force.

The vacuum mixing device therefore does not require any energy stores orany electric or electronic drives. This is desirable since the vacuummixing device is intended for one-time use and in this way can berecycled more easily. In addition, the vacuum mixing device is ready foruse in principle, and does not require any connections, such as cablesor compressed gas tubes, in order to be used.

With a development of the vacuum mixing system, provision can be made sothat the vacuum pump and the pressure pump are embodied as a combinedpressure-vacuum pump, wherein the vacuum plunger and pump plunger arepreferably formed in one part or are connected to one another via aconnection, in particular via a rod or a pipe.

The design is thus simplified. In addition, the pump plunger and thevacuum plunger can thus be easily driven together, such that there is noneed for separate or combined connections at the operating element. Thepump plunger and the vacuum plunger thus in any case run in asynchronous manner. The overall design can also thus be made morecompact and simpler.

Here, provision can be made so that the distance between the sides ofthe vacuum plunger and of the pump plunger facing away from one anotheris at least exactly the same as the maximum stroke of the vacuum plungerand the pump plunger.

In this way, it is possible to prevent the inflow for the monomer liquidfrom the receptacle or the integrated container from being connected tothe vacuum pump chamber. This inflow is preferably positioned in such away that it is arranged in the lateral surface of the pump plungerchamber in a manner bordering or in the direct vicinity of the pumpplunger in its starting position, such that the inflow is already runpast and thus closed by the pump plunger at the start of the firststroke. The inflow then lies accordingly within the range of the vacuumplunger, so that, as a result of the spacing, it is possible to preventmonomer liquid from passing into the vacuum pump chamber. Alternatively,a closure device can also be provided, which tightly closes the inflowat the time of the first movement of the pump plunger.

With a particularly preferred embodiment of the present invention,provision can be made so that the pump plunger is movable only in onedirection in order to reduce the size of the pressure pump chamber andthen cannot be moved back in the opposite direction, and preferably ismovable by the connection only in a direction for reducing the size ofthe pressure pump chamber.

It can thus be ensured that the pressure pump chamber is not made largeragain, such that the interior of the cartridge can be further evacuatedas a result of further operation of the vacuum pump, without air beingable to then flow in from the pressure pump chamber or via the openreceptacle or the open internal container. The pump plunger for thispurpose, preferably in its end position, closes the fluid connection orthe mouth to the fluid connection.

The objects forming the basis of the present invention are also achievedby a method for mixing polymethylmethacrylate bone cement in an interiorof a cartridge of a vacuum mixing device, in particular a vacuum mixingdevice of the type described above, in which method

an operating element is operated and an integrated container of thevacuum mixing device or a separate container, which is arranged in areceptacle of the vacuum mixing device, is thus opened, wherein amonomer liquid contained in the integrated container or the separatecontainer then flows as first component of the bone cement into a pumpchamber of a pressure pump,

by means of a subsequent, further operation of the operating element, amovement of a vacuum plunger of a vacuum pump of the vacuum mixingdevice is driven, wherein a negative pressure is generated in a vacuumpump chamber of the vacuum pump by means of the movement of the vacuumplunger, wherein the interior of the cartridge is evacuated by means ofthe vacuum pump driven in this way,

a movement of a pump plunger of a pressure pump of the vacuum mixingdevice is driven by the further operation of the operating element,wherein a pressure is exerted onto the monomer liquid in the pumpchamber by means of the movement of the pump plunger and the monomerliquid is pushed from the pump chamber into the interior of thecartridge, wherein a bone cement powder as second component of the bonecement is already disposed in the interior of the cartridge, and

a mixing device in the interior of the cartridge is moved as a result ofthe operation of the operating element and a bone cement dough in theinterior of the cartridge formed from cement powder and the monomerliquid is mixed as a result of the movement of the mixing device.

Here, provision can be made so that the volume of a vacuum pump chamberof the vacuum pump is increased by the manual movement of the vacuumplunger and the interior of the cartridge is evacuated due to thenegative pressure created as a result.

Alternatively or additionally, provision can be made so that the volumeof the pressure pump chamber of the pressure pump is made smaller by themanual movement of the pump plunger and the monomer liquid is pushedfrom the pressure pump chamber into the interior of the cartridge due tothe pressure created as a result.

The vacuum pump or the pressure pump can thus be provided in a simpleway.

Provision can also be made in accordance with the invention so that acement powder is contained in the interior of the cartridge and a gas isevacuated from the interior of the cartridge by means of the vacuumpump, a monomer liquid is pushed into the interior of the cartridge bymeans of the pressure pump, and the monomer liquid is mixed with thecement powder in the evacuated interior of the cartridge due to amovement of the mixing device.

A design that can be provided particularly easily and reliably can beachieved as a result of the specified combination and interaction of themethod steps.

Furthermore, provision can be made so that the vacuum plunger of thevacuum pump is moved by means of the operating element, whereby anegative pressure relative to the surrounding atmosphere is generated inthe vacuum pump, in so doing gas from the interior of the cartridge issucked into the vacuum pump chamber of the vacuum pump through aconnection line, and the pump plunger of the pressure pump is moved bymeans of the operating element, whereby a pressure is exerted onto themonomer liquid in the pressure pump chamber, the monomer liquid ispushed through a fluid connection from the pressure pump chamber intothe interior of the cartridge, the vacuum mixing device in the interiorof the cartridge is then moved by operation of the same operatingelement, and in so doing the cement powder is mixed with the monomerliquid, the cartridge containing the mixed cement dough is removed, andthe cement dough is pressed out from the cartridge by means of an axialmovement of a dispensing plunger.

The method is hereby enhanced such that, at the end, a cement cartridgecontaining a bone cement dough mixed under vacuum is provided and can beused immediately.

Lastly, provision can also be made so that the cement powder is arrangedin the cartridge, the monomer liquid is arranged in a receptacleseparate from the cartridge, wherein the monomer liquid is contained inan integrated container or in a separate container, preferably in aglass ampoule in the receptacle, the integrated container or theseparate container is opened by operation of the operating element and aresultant movement of the opening device, before the vacuum plunger andthe pump plunger are driven by a further operation of the operatingelement, the vacuum plunger and the pump plunger are then moved axiallyin a hollow cylinder, in so doing gas from the interior of the cartridgeis sucked through the connection line into the vacuum pump chamberdelimited by the hollow cylinder, and the monomer liquid disposed in thepressure pump chamber delimited by the hollow cylinder is pushed throughthe fluid connection into the interior of the cartridge.

The method is thus further enhanced.

Methods according to the invention can also be characterised by theintended application or use of component parts of vacuum mixing devicesaccording to the invention.

The invention is based on the surprising finding that it is possiblewith a single operating element to operate or drive the vacuum pump, thepressure pump (or the combined pressure-vacuum pump) and the mixingdevice and also to operate and drive the opening device. This has theadvantage that there is no need for any complicated handlinginstructions for the operating individual. All sequences can becontrolled and driven by operation of the sole operating element. Thevacuum mixing device is thus simplified to the greatest possible extent.At the same time, there is no need for any energy stores for the drive,and there is no need for any electrical or electronic control unit inorder to drive and control the vacuum pump, the pressure pump, themixing device and the opening device.

At the same time, it is possible with the aid of the vacuum pump, whichis to be driven manually, and the pressure pump, which is also to bedriven manually, to provide a vacuum mixing device that is independentof internal and external power sources and other supply lines. Thevacuum mixing device according to the invention can be constructed in acompact, simple and space-saving manner. The vacuum pump, the pressurepump, the opening device, and the entire vacuum mixing device can beconstructed using the simplest means, such that the entire vacuum mixingdevice can be used as a disposable system. The pressure pump is used totransfer a monomer liquid into the cement powder, whereas the vacuumpump is used primarily in order to evacuate the interior of thecartridge so that the bone cement is mixable under negative pressure orunder vacuum. The vacuum or the negative pressure in the interior of thecartridge additionally assists the transport of the monomer liquid intothe interior of the cartridge, since the monomer liquid is suctionedthrough the fluid connection. The two components of the PMMA bone cementcan then be mixed in the vacuum or in the negative pressure.

A device for generating a vacuum or for generating a negative pressureis contained in the cementing systems according to the present inventionand is suitable for the temporary generation of a negative pressurebefore and during the mixing of a powdered component with a liquidmonomer component of the polymethylmethacrylate bone cement.

The idea forming the basis of the invention is based on the finding thatonly a relatively small amount of energy and therefore a low manualapplication of force is necessary in order to open the container for themonomer liquid in order to push the monomer liquid into the interior ofthe cartridge in order to generate the vacuum or the negative pressurein a cartridge, which is necessary in order to mix the startingcomponents of a bone cement under the negative pressure or the vacuum,and in order to move the mixing device for mixing the bone cement doughin the interior of the cartridge. This small amount of energy can beapplied readily by operation of a lever as operating element. The vacuummixing device hereby can be handled in a simple manner and is easilyoperated and is also independent of internal and external energy stores.Due to a suitable structure, the order of the sequences can also becontrolled, specifically the monomer container can be opened first andonly then can the vacuum pump, the pressure pump, and the mixing devicebe driven.

The idea of the invention is also based on the fact that a negativepressure is generated in a hollow cylinder of the vacuum pump by manualactuation of an operating element with a vacuum plunger connectedthereto in the hollow cylinder of the vacuum pump, wherein the negativepressure spreads via a line means into the cartridge, a pressure in ahollow cylinder of the pressure pump is, at the same time, exerted ontothe monomer liquid contained therein by manual actuation of an operatingelement with a pump plunger connected thereto in the hollow cylinder ofthe pressure pump or in the same hollow cylinder of the pressure pumpembodied as a combined pressure-vacuum pump, and the monomer liquid ispushed and sucked into the cartridge, in which cement powder isdisposed. The cement components are then mixed manually with the aid ofa mixing device, which is to be driven simultaneously via the sameoperating element.

By way of example, the invention can be implemented by means of thefollowing method, in which the following functions are performed in themixing device by activation with a manually operated lever or moregenerally a manually operated operating element:

1^(st) step: actuation of the manual lever or operating element andbreaking of the ampoule or ampoules, leakage of the monomer liquidwithin 1 to 2 seconds into the pump chamber, which is connected to aline means (of the fluid connection) and a nozzle, wherein the nozzlepoints via its opening into the interior of the cartridge; latching of aresilient rod into a mating detent means of the lever at the stop pointof the lever, wherein the rod is forked into a first part and a secondpart;

2^(nd) step: return movement of the manual lever or operating elementinto the starting position, wherein a vacuum plunger and a pump plungerin a hollow cylinder are moved axially by the first part of theresilient rod and a negative pressure is created behind the vacuumplunger in the hollow cylinder and a pressure behind the pump plunger isexerted onto the monomer liquid in the pump chamber in the hollowcylinder; forwarding of the negative pressure via a check valve and aline means for vacuum connection into the interior of the cartridge;creation of a negative pressure in the interior of the cartridge;pushing of the monomer liquid from the pump chamber, through the fluidconnection and a nozzle, into the cartridge, and parallel suctioning ofthe monomer liquid from the pump chamber into the cartridge; movement ofthe second part of the resilient rod, which is rotatably connected to afirst sleeve, which has at least one outermost lobe, which is arrangedmovably in a steep thread of a second sleeve, such that a resilientstirring bar (as mixing shaft) is fixedly connected to the first sleeveso that the first sleeve is rotated by engagement of the lobe in thesteep thread in the event of an axial movement of the first sleevethrough the (or in the) second sleeve, whereby the stirring bar rotatesand moves axially in the cartridge;

3^(rd) step: further actuation of the manual lever or operating element;movement of the first sleeve in the second sleeve; axial movement of thestirring bar in the cartridge with rotation about the longitudinal axis;

4^(th) step: repetition of the 2^(nd) and 3^(rd) steps until the cementdough is homogeneously mixed;

5^(th) step: release of the cartridge or cartridge system by unscrewingand removal of the mixing bar (of the mixing shaft) with the mixingelement; and collapsing of the mixing elements (the mixing blades of themixing device).

The key advantage of the invention is that a prepacked mixing system isproposed which can be used in the simplest manner possible, withoutspecific training measures, by the medical user by means of simplemanual actuation in order to produce a polymethylmethacrylate bonecement dough within a few seconds (for example within 40 seconds). It isalso advantageous that use errors are minimised on account of themaximally simplified operation, thus resulting in an improvement inpatient safety.

The vacuum mixing device according to the invention can be providedsubstantially inexpensively using simple plastics material parts to beproduced by plastics material injection moulding. The particularadvantage of the device according to the invention lies in the fact thatthe device is operatable without external aids, such as vacuum pumps andpressure pumps driven by compressed air, and without vacuum tubes, andwithout energy sources, such as compressed air or batteries. The vacuummixing device according to the invention can be used autonomously andcan be used even under the simplest or most difficult operationconditions. A closed full-prepacked vacuum cementing system forprice-sensitive markets is provided by means of the vacuum mixing deviceaccording to the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

Further exemplary embodiments of the invention will be explainedhereinafter on the basis of nine schematically illustrated Figures,without, however, intending to limit the invention hereto. In theFigures:

FIG. 1: shows a schematic perspective view of a vacuum mixing deviceaccording to the invention;

FIG. 2: shows a schematic perspective view of the vacuum mixing deviceaccording to FIG. 1 with open housing;

FIG. 3: shows a schematic perspective view of the vacuum mixing deviceaccording to FIGS. 1 and 2 with the housing opened on the other side(compared to FIG. 2);

FIG. 4: shows a schematic perspective cross-sectional view of the vacuummixing device according to FIGS. 1 to 3 in the starting state;

FIG. 5: shows a schematic cross-sectional view of the vacuum mixingdevice according to FIGS. 1 to 4 in the starting state;

FIG. 6: shows a schematic cross-sectional view of the vacuum mixingdevice according to FIGS. 1 to 5 with a plane of section perpendicularto the section of FIGS. 4 and 5;

FIG. 7: shows a schematic cross-sectional view of the vacuum mixingdevice according to FIGS. 1 to 6 during the operation with broken-openglass ampoule;

FIG. 8: shows a schematic cross-sectional view of the vacuum mixingdevice according to FIGS. 1 to 7 during the operation with latched cableor latched rod; and

FIG. 9: shows a schematic cross-sectional view of the vacuum mixingdevice according to FIGS. 1 to 8 during the operation at the time ofpumping and mixing.

DETAILED DESCRIPTION OF THE DISCLOSURE

FIGS. 1 to 9 show various views of a vacuum mixing device according tothe invention before and during operation. The vacuum mixing deviceconsists fundamentally of five parts, specifically a cartridge system 1,a liquid container 2, a combined pressure-vacuum pump 3, which is to bedriven manually, an operating element 4, and an opening device 5.

A central part of the cartridge system 1 is a cartridge 6 having acylindrical interior which is closed at its upper side by a two-partdispensing plunger 8 which is arranged movably in a longitudinaldirection in the cylindrical interior of the cartridge 6. The cartridge6 thus has a cylindrical interior with circular base area. The cartridge6 contains a cement powder 9 as starting component for a bone cement.

A mixing device 10 having two or more mixing blades 10 is also arrangedin the interior of the cartridge 6, wherein the mixing device 10 ismounted rotatably and displaceably in the longitudinal direction in theinterior of the cartridge 6 and is secured to a mixing shaft 12 or to acable 12, which is guided rotatably and displaceably in the longitudinaldirection through a feedthrough in the underside of the cartridge 6 intothe interior of the cartridge 6. The feedthrough is pressure-tight andgas-tight for this purpose. The mixing shaft 12 can also be embodied asa flexible rod 12.

The cartridge system 1 is connected to the liquid container 2 and thepressure vacuum pump 3 via a base part 18 and a housing 19. The liquidcontainer 2, the pressure-vacuum pump 3, part of the operating element4, and the opening device 5 are surrounded by the housing 19, whereinpart of the operating element 4 protrudes from the housing 19, whereasthe cartridge system 1 is screwed onto the housing 19. The cartridge 6ends at its underside in a connection piece having an internal thread14, which is screwed onto an external thread 16 on a connection piece ofthe housing 19. The base part 18 here forms the stand 18 of the compactvacuum mixing device. The cartridge 6 is thus releasable from thehousing 19 and therefore the rest of the vacuum mixing device. When thebone cement 96 (see FIG. 9) is mixed to a finished state in the interiorof the cartridge 6 by means of the vacuum mixing device, the cartridge 6can thus be unscrewed from the housing 19, and a dispensing pipe (notshown) can be screwed into the internal thread 14, through which pipethe finished bone cement dough 96 (see FIG. 9) can be driven out byadvancing the dispensing plunger 8 in the direction of the internalthread 14. A static mixer can be provided in the dispensing pipe, whichmixer provides an additional mixing of the bone cement dough 96.

The two-part dispensing plunger 8 has a sealing plunger 20 and asterilisation plunger 22. The sterilisation plunger 22 has a membrane orpore plate 24, which is permeable for a sterilising gas, but is notpermeable for the cement powder 9. The sterilisation plunger 22 isinserted into the cartridge 6 once the cement powder 9 has been filledtherein and closes the interior of the cartridge 6 with respect to theoutside. The content in the cartridge 6 can then be sterilised withethylene dioxide through the gas-permeable membrane or pore plate 24.

This sealing plunger 20 can be pushed into the sterilisation plunger 22and can be connected thereto in a gas-tight and pressure-tight manner.The plunger parts 20, 22 secured to one another then together form thedispensing plunger 8, by means of which the content in the cartridge 6can be pressed out through the opening in the connection piece havingthe internal thread 14. The sterilisation plunger 22 is initially lockedon the side opposite the side with the opening in the connection piecehaving the internal thread 14 (at the top in FIGS. 3 to 5 and 7 to 9),wherein the locking is releasable. As a result of the locking, thesterilisation plunger 22 is prevented from moving undesirably during thesterilisation of the interior of the cartridge 6 and also the cementpowder 9.

The mixing blades 10 inside the cartridge 6, i.e. in the interior of thecartridge 6, can be rotated via the mixing shaft 12 or the cable 12 andare movable in the longitudinal direction of the cartridge 6.

A feedthrough is provided in the sealing plunger 20, which feedthroughis connected to a connection line 26 in the form of a flexible vacuumline 26. This sealing plunger 20 is otherwise closed in a pressure-tightmanner with the cartridge 6.

The combined pressure-vacuum pump 3 comprises a vacuum pump 3, which isformed by the front part of the combined pressure-vacuum pump 3 (on theleft in FIGS. 2, 4, 5 and 7 to 9, on the right in FIG. 3, and at the topin FIG. 6), and a pressure pump 3, which is formed by the rear part ofthe combined pressure-vacuum pump 3 (on the right in FIGS. 2, 4, 5 and 7to 9, on the left in FIG. 3, and at the bottom in FIG. 6).

The vacuum line 26 opens via a first check valve 27 into the vacuum pump3, such that only a flow in the direction into the vacuum pump 3 ispossible. The vacuum pump 3 is additionally connected to thesurroundings via a second check valve 28, such that an overpressurecreated in the vacuum pump 3 can be discharged via the second checkvalve 28. Details regarding the check valves 27, 28 are illustrated inFIG. 6 and will be described further below in the description. A filter(not shown) can be provided optionally at the second check valve 28, bymeans of which filter methacrylate vapours or other disruptive chemicalsubstances can be filtered out from the gas flowing out.

The pressure-vacuum pump 3 is constructed with a common stable hollowcylinder 29, which connects the two parts of the pressure-vacuum pump 3,i.e. the vacuum pump 3 and the pressure pump 3. The hollow cylinder 29is separated in a pressure-tight manner into three parts via a vacuumplunger 30 and via a pump plunger 31. For this purpose, the vacuumplunger 30 and the pump plunger 31 have peripheral seals 32, whichterminate with the inner wall of the hollow cylinder 29. The vacuumplunger 30 and the pump plunger 31 are connected to a cable 34 or aflexible rod 34 made of a stable resilient plastics material or made ofa metal, such as steel, which leads through a feedthrough in a rear-sideclosure 33. The vacuum plunger 30 and the pump plunger 31 are fixedlyconnected to one another via a pipe 35 or a rod 35, such that thedistance between the vacuum plunger 30 and the pump plunger 31 in thepressure-vacuum pump 3 is fixed.

On the front side, the vacuum pump 3 is closed by a front-side closure,in which there are disposed the connections for the check valves 27, 28.The closure 33 is connected on the sides of the hollow cylinder 29opposite the check valves 27, 28. The vacuum line 26 is guided as far asthe vacuum pump 3, such that the feedthrough in the sealing plunger 20is connected in a pressure-tight manner via the vacuum line 26 to thevacuum pump 3, more specifically to a vacuum pump chamber 94 (see FIG.9) of the vacuum pump 3. The vacuum pump chamber 94 is delimited by theinner walls of the hollow cylinder 29, by the front-side closure, and bythe vacuum plunger 30. In the case of the pressure pump 3, a pressurepump chamber 36 is delimited by the hollow cylinder 29, by the pumpplunger 31, and by the closure 33. The space between the vacuum plunger30 and the pump plunger 31 is not used apart from to prevent theinfiltration of monomer liquid into the vacuum pump chamber 94.

The cable 34 is connected to a detent means 37, which can latch with amating detent means 38 (see FIGS. 8 and 9). The mating detent means 38is part of the operating element 4, which is constructed as a lever 4which can be rotated or pivoted about an axis 40. The lever 4 comprisestwo lever arms 41, 42, which extend from the axis 40 in differentdirections. The actual operating part of the lever 4 is formed by thefirst lever arm 41, which ends in a handle 44, which can be manuallyoperated from outside. The first lever arm 41 thus protrudes out fromthe housing 19, and the handle 44 is arranged outside the housing 19 andcan be manually operated by the user of the vacuum mixing device. Here,a considerable force can be transferred into the interior of the vacuummixing device via the first lever arm 41 and is sufficient and is usedin accordance with the invention to drive the opening device 5, thevacuum pump 3, the pressure pump 3, or the pressure-vacuum pump 3, andthe mixing device 10.

The second lever arm 42, as the lever 4 is pivoted or as the lever 4 ispushed down, pushes against the opening device 5 and drives this. Forthis purpose, the opening device 5 is constructed with a lever 46, whichis mounted so as to be rotatable or pivotable about an axis 47. At theend of the lever 46 opposite the axis 47, an insert having an edge 48 isprovided, which bears against the receptacle 2 or the liquid container2.

The liquid container 2 or the receptacle 2 comprises an inner resilientinsert 50, which for example can consist of a rubber, and a rigid hollowcylinder 52 made of a plastics material, such as plastic. A glassampoule 54 containing a monomer liquid is inserted into the receptacle 2or the liquid container 2. The monomer liquid forms a bone cement dough96 together with the cement powder 9 from the cartridge 6 when these aremixed together. The inner walls of the resilient insert 50 bear againstthe glass ampoule 54. The glass ampoule 54 has an ampoule head 56 and anampoule base 58 opposite the ampoule head 56. The glass ampoule 54 sitsvia the ampoule base 58 on a support 60, which is formed as a shoulder60 of the resilient insert 50. At the upper side, a hollow cylinder 62made of a gas-permeable foam material and which is secured to the innerside of the housing 19 pushes the glass ampoule 54 against the support60. Openings are provided between the hollow cylinder 52 and the housing19, through which openings air or gas from the surroundings of thereceptacle 2 and the vacuum mixing device can flow into the receptacle2. The monomer liquid can thus flow out from the receptacle 2 moreeasily. The openings between the hollow cylinder 52 and the housing 19are formed in such a way that they are arranged in the lateral cylinderwall of the hollow cylinder 52 in a manner bordering the upper base areaof the hollow cylinder 52. The hollow cylinder 52 thus bears only inregions against the housing 19. Air can flow therebetween into theinterior of the receptacle 2.

In the region of the ampoule base 58 or the support 60, the hollowcylinder 52 has a recess, within which the edge 48 bears against theresilient insert 50, such that the ampoule base 58 is broken open by theopening device 5 and therefore the glass ampoule 54 can be opened. Theampoule head 56 of the glass ampoule 54 is usually broken open in orderto open the glass ampoule 54. Since the glass ampoule 54 is thin at theneck, this means that the monomer liquid can run out only slowly fromthe glass ampoule 54 and therefore the user must wait until they canperform the next steps for operating the vacuum mixing device. This isnot suitable in the case of the largely automated method, which isdriven by operation of the lever 4 or the operating element 4, since itis not possible to ensure that the monomer liquid from the glass ampoule54 will be available yet when the vacuum pump 3 is driven via theoperating element 4.

The glass ampoule 54 pushes into the insert 50 made of the deformablematerial. The insert 50 together with the hollow cylinder 52 forms theessential parts of the receptacle 2 for the glass ampoule 54. The glassampoule 54 can be pushed into the insert 50 of the liquid container 2only as far as the ampoule base 58 on account of the shoulder 60.

The liquid container 2 has a lateral opening, in which the insert 50forms a deformable side wall. At this point, the glass ampoule 54 can beopened or broken open by application of a pressure onto the glassampoule 54 by the deformable side wall 50 just above the ampoule base58. When the ampoule base 58 of the glass ampoule 54 is broken open orthe glass ampoule 54 is opened, the monomer liquid can flow out from theopen glass ampoule 54 over the entire cross-section, such that themonomer liquid is quickly available in its entirety for furtherprocessing within the vacuum mixing device.

In order to deform the deformable side wall 50 and thus break open theglass ampoule 54, the lever 42 is used, which can be operated via thelever 4 and which can be rotated about the axis 40. The lever 4 ismounted pivotably or rotatably about the axis 40 relative to the housing19. The axis 40 divides the lever 4 into a long lever arm 41, to whichthe handle 44 is secured, and a short lever arm 42, which is arrangedinside the housing 19. At the start, the long lever arm 41 can only bemoved away from the liquid container 2 and not towards said container,since the long lever arm 41 bears at the top against the opening of thehousing 19 and thus prevents a further movement in this direction.

The short lever arm 42 of the lever 4 bears on its side facing towardsthe liquid container 2 against the lever 46 of the opening device 5,which is connected to the base part 18 or the housing 19 of the vacuummixing device via a joint 47 or the axis 47 in a manner rotatable aboutthe axis 47. This lever 46 of the opening device 5 is arranged insidethe housing 19. The free lever end of the lever 46 in the housing 19 ismovable by means of the short lever arm 42. At the tip of the free leverend, the edge 48 is secured and bears against the deformable side wall5. The axis 47 of the lever 46 is arranged here such that the free leverarm and therefore the edge 48 moves in the direction of the deformableside wall 5 and in the direction of the base part 18. The force that canbe exerted from the edge 48 through the deformable side wall 50 onto theglass ampoule 54 thus also pushes the glass ampoule 54 lightly in thedirection of the shoulder 60 and thus presses the glass ampoule 54 intothe receptacle 2.

A sieve 64 and/or a filter 64 are/is arranged below the shoulder 60, bymeans of which sieve and/or filter glass splinters of the opened orbroken-open glass ampoule 54 are held back. The distance between theshoulder 60 and the sieve 64 and/or filter 64 is greater than the outerdiameter of the glass ampoule 54, such that the dropping ampoule base 58can rotate in a gap 66 and the flow of monomer liquid from the openedglass ampoule 54 is not hindered (see FIGS. 7 to 9). A funnel 68 isarranged below the sieve 54 and/or filter 64 and opens out into thepressure pump chamber 36. The mouth of the funnel 68 is arranged tightlywith the pump plunger 31 in its starting position, such that the pumpplunger 31 covers the mouth just before the start of the movement of thepump plunger 31 and monomer liquid is not pushed back continuously intothe receptacle 2. The pressure pump chamber 36 is connected via a mouth25 to a fluid connection 70, which is connected to the interior of thecartridge 6. The front side of the cartridge 6 (at the bottom in FIGS. 1to 5 and 79) is tightly connected to the pressure pump chamber 36 by thebase part 18 and the housing 19 via the fluid connection 70 to the mouth25.

The cartridge 6 is releasably secured perpendicularly on the housing 19.The fluid connection 70 opens out in the connection piece having theexternal thread 16 through a filter 72 impermeable to powder butpermeable for the monomer liquid into the interior of the cartridge 6.An annular channel 73 (denoted only in FIGS. 3, 4 and 9, but alsovisible in FIGS. 5, 7 and 8) is formed beneath the filter 72 and is opentowards the filter 72, such that the filter 72, which is likewiseannular, covers the annular channel. The annular channel 73, into whichthe fluid connection 70 opens out and which strictly speaking alsobelongs to the fluid connection 70, and the annular filter 72 surroundthe passage in which the mixing shaft 12 or the cable 12 is guided inthe interior of the cartridge 6. Seals (not shown) or at least scrapers(not shown) can be provided in the passage for this purpose. As a resultof the annular channel 73, the monomer liquid is introduced through thefilter 72 around the mixing shaft 12 into the interior of the cartridge6. A nozzle (not shown) can also be provided at the entry of the fluidconnection 70 into the interior of the cartridge 6, which nozzledistributes the monomer liquid in the interior or in the cement powder9.

The liquid container 2 is closed upwardly by means of the housing 19once the glass ampoule 54 has been inserted into the liquid container 2.So that the monomer liquid can run out or run off from the glass ampoule54 and the gap 66 without difficulty, a number of passages (not shown)can additionally be provided in the part of the housing 19 covering theliquid container 2, through which air from outside can flow into theliquid container 2. Once the glass ampoule 54 has been broken open, themonomer liquid flows through the gap 66 and the funnel 68 into thepressure pump chamber 36 and can be pushed through the fluid connection70 into the interior of the cartridge 6, in which a pressure is exertedby means of the pump plunger 31 onto the monomer liquid in the pressurepump chamber 36. At the same time, a negative pressure is generated inthe interior of the cartridge 6, by means of which pressure the monomerliquid is sucked from the pressure pump chamber 36 into the interior ofthe cartridge 6. This negative pressure is generated by means of thevacuum pump 3. In the interior of the cartridge 6, the monomer liquidcan then be mixed with the cement powder 9 with the aid of the mixingdevice 10 under vacuum or under negative pressure in order to producethe bone cement 96 or a bone cement dough 96.

The mixing device 10 is used to mix the content in the interior of thecartridge 6. The cable 12 or the mixing shaft 12, via which the mixingdevice 10 is rotated in the interior and is moved up and down in thelongitudinal direction of the interior, is deflected via pins 74 ordeflection rollers 74 in the direction of a cylinder 76. The deflectionrollers 74 can be reconstructed with spring-mounted tubes or deflectionsleeves. Here, the springs serve merely to fix the deflection rollers 74or deflection sleeves. The cable 12 or the mixing shaft 12 is rigidlyconnected to the cylinder 76. The cylinder 76 has a steep externalthread 78 on the outer side. The cylinder 76 is arranged in a sleeve 80having an internal thread 82 matching the external thread 78. As thecylinder 76 is moved in the sleeve 80 in the longitudinal direction (ofthe cylinder axis), the mixing device 10 is thus moved via the cable 12or the mixing shaft 12 in the longitudinal direction of the interior ofthe cartridge 6 and at the same time is rotated about the mixing shaft12 on account of the threads 78, 82, and the content in the interior isthus mixed. Alternatively to the external thread 78 on the sleeve, oneor more protrusions or one or more lobes 78 can also be provided, whichrun in the internal thread 82 and thus rotate the cylinder 76 in thesleeve 80.

The cylinder 76 is connected via a ball joint or a ball joint head 84 toa rigid cable 86 or a flexible rod 86, which is constructed similarly tothe cable 34 or the flexible rod 34 for the pressure-vacuum pump 3. Theball joint head 84 can thus move within a receptacle for the ball jointhead 84 of the cylinder 76 and can rotate therein. It is thus madepossible, as the cable 86 moves, for a rotation of the cylinder 76 inthe sleeve 80 to be enforced at the same time. The cable 86, which isconnected to the cylinder 76, and the cable 34, which is connected tothe pump plunger 31 of the pressure-vacuum pump 3, are connected to oneanother, wherein both are positioned via pins 88 or deflection rollers88. The defection rollers 88 are constructed similarly to the deflectionrollers 74. The connection of the cable 34 to the pump plunger 31 canalso be constructed by means of a ball joint. The two cables 34, 86 orflexible rods 34, 86 are joined together to form a cable 90 or aflexible rod 90 which is guided upwardly to the lever 4 or to theoperating element 4, wherein the cable 90 or the flexible rod 90 endsthere in the detent means 37. The cable 90 is also constructed similarlyto the cable 34 for the pressure-vacuum pump 3, or the flexible rod 90is constructed similarly to the flexible rod 34 for the pressure-vacuumpump 3. The cables 34, 86, 90 connected in a forked manner or the forkedrods 34, 86, 90 can be produced from a plastics material by injectionmoulding, or the common forked cable 34, 86, 90 or the forked rod 34,86, 90 can be produced from a plastics material by injection moulding.The detent means 37 at the end of the cable 90 is mounted here andpretensioned such that it engages with the mating detent means 38 andlatches therewith when the lever 4 is rotated or pivoted or when themating detent means 38 is pivoted at the height of the detent means 37.

The maximum stroke, which is determined by a rounded portion on thelever 4 formed as an involute 83, the cable 90 or the flexible rod 90being brought up to the involute 83 following successful latching, issufficient for the mixing device 10 to be passed through the interior ofthe cartridge 6 over the entire length thereof. This can be seen inFIGS. 3, 4, 5, 7 and 8 in comparison with FIG. 9, since with a completestroke of the lever 4, which is illustrated in FIG. 9, the mixing device10 or the mixing blades 10 bears/bear on the filter 72 at the front sideof the interior of the cartridge 6, whereas without stroke, asillustrated in FIG. 8, the mixing device 10 or the mixing blades 10bears/bear against the dispensing plunger 8 or the sterilisation plunger22 and the pore plate 24 on the rear side of the interior of thecartridge 6. A complete mixing of the interior of the cartridge 6 withthe mixing device 10 is thus made possible. The mating detent means 38is for this purpose arranged at the end of the involute 83 facing awayfrom the pulling direction of the cables 90, 34, 86 or the flexible rods90, 34, 86 so that the cable 90 or the flexible rod 90 can be brought upover a wide area of the involute 83.

Instead of connecting the cable 34 or other flexible rod 34 of thepressure-vacuum pump 3 and the cable 86 or the flexible rod 86 of thecylinder 76 to one another to form the cable 90 or the flexible rod 90,on which the detent means 37 is arranged, each of the cables 34, 86 oreach of the flexible rods 34, 86 can just as easily have its own detentmeans, which engages with the mating detent means 38 or the twodifferent mating detent means at the end of the involute 83 or the lever4 and latches therewith.

In an alternative embodiment of a mixing device according to theinvention, the cable 12 can be directly connected to the cable 86, orthe two cables 12, 86 can be formed as a common continuous cable, or theflexible rod 12 can be formed in one part with the flexible rod 86. Thecylinder 76, the sleeve 80, and the threads 78, 82 are then superfluousand are not provided. This leads to the mixing device 10 no longer beingrotated by the mixing shaft 12 in the interior of the cartridge 6. Amixing of the interior of the cartridge 6 is then still achieved only bythe movement up and down of the mixing device 10 in the longitudinaldirection. By means of a suitable inclination of the mixing blades 10 orsome of the mixing blades 10 and/or by a guidance of at least oneprotrusion (not shown) on the mixing device 10 in at least one spiralledgroove (not shown) in the inner wall of the cartridge 6, a rotation ofthe mixing device 10 in the cartridge 6 can also be enforced in anotherway, provided the rotation of the mixing device 10 in the cartridge 6 isnot easily foregone.

FIG. 6 shows a schematic cross-sectional view of the vacuum mixingdevice according to FIGS. 1 to 5 and 7 to 9 with a plane of sectionperpendicular to the section in FIGS. 4 and 5 and 7 to 9. Inter alia, anexemplary construction of the check valves 27, 28 is explained herein.The check valves 27, 28 are constructed with balls 91, which are pushedby springs 92 onto a ball seat, in which the connection to the vacuumline 26 or to the surroundings of the vacuum pump 3 is disposed. Whenthe balls 91 are pushed onto the ball seat, these connections areclosed. The check valve 27 opens when a negative pressure relative tothe pressure in the vacuum line 26 or relative to the interior of thecartridge 6 is created or provided in the vacuum pump 3 by moving thevacuum plunger 30 in the direction of the closure 33, i.e. when thevacuum pump chamber 94 (see FIG. 9) opens. The check valve 28 bycontrast opens when a pressure greater than that in the surroundingsprevails in the vacuum pump chamber 94 or in the vacuum pump 3.Otherwise, the check valves 27, 28 close on account of the spring forceof the springs 92.

The vacuum mixing device is characterised in accordance with theinvention by the applicability of the following exemplary methodaccording to the invention. The monomer liquid is provided in thereceptacle 2 by breaking open the glass ampoule 54 by means of theopening device 5, as explained above. For this purpose, the lever 4,which is disposed originally in an upright position (see FIGS. 1 to 5)is pushed down (see FIG. 7). Whilst the monomer liquid flows into thepressure pump chamber 36, the lever 4 is rotated or pivoted further,until the mating detent means 38 is rotated at the height of the detentmeans 37 and both latch with one another (see FIG. 8). By means of thelatching of the detent means 37 with the mating detent means 38, thevacuum pump 3 and the pressure pump 3 can now be moved or driven bymeans of the lever 4 via the cable 34, 90 or the flexible rod 34, 90,and the mixing device 10 can be driven by means of the lever 4 via thecable 86, 90 or the rod 86, 90, the cylinder 76, and the cable 12 or themixing shaft 12. For this purpose, the lever 4 is rotated or pivotedaway from the lower stop, back into the starting position (FIGS. 2 to5).

The vacuum pump 3 of the combined pressure-vacuum pump 3 is used in thatthe vacuum plunger 30 is drawn by means of the operating element 4 viathe cable 34, 90 or the flexible rod 34, 90 away from the check valves27, 28 in the direction of the closure 33. In so doing, the vacuum pumpchamber 94 inside the vacuum pump 3 opens (see FIG. 9). Due to theenlargement of the vacuum pump chamber 94, a lower pressure is generatedin the vacuum pump chamber 94. This leads to an opening of the checkvalve 27, so that gas is sucked or pushed from the interior of thecartridge 6, through the connection line 26, into the vacuum pumpchamber 94. On account of the resultant negative pressure, the monomerliquid is sucked from the pressure pump chamber 36, through the fluidconnection 70, into the interior of the cartridge 6.

The pressure pump 3 of the combined pressure-vacuum pump 3 is used inthat the pump plunger 31 is drawn by means of the operating element 4via the cable 34, 90 or the flexible rod 34, 90 away from the checkvalves 27, 28 in the direction of the closure 33. In so doing, thepressure pump chamber 36 in the interior of the pressure pump 3 becomessmaller. Due to the reduction in size of the pressure pump chamber 36,the monomer liquid is pushed from the pressure pump chamber 36, throughthe mouth 25 and the fluid connection 70, the annular channel 73 and thefilter 74, into the interior of the cartridge 6.

The pump plunger 31 is moved as far as the end of the hollow cylinder 29(on the right in FIGS. 3 to 5 and 7 to 9). This arrangement is shown inFIG. 9. The volume increase of the vacuum pump chamber 94 can preferablybe sufficient to evacuate the gas from the vacuum line 26, the interiorof the cartridge 6, and the fluid connection 70, and to draw the monomerliquid from the liquid container 2 into the interior of the cartridge 6.The expanded vacuum pump chamber 94 for this purpose can preferably belarger than the volumes of the lines 26, 70, the interior of thecartridge 6, and the liquid volume of the monomer liquid. The vacuumpump chamber 94 in accordance with the invention can thus preferably belarger than the pressure pump chamber 36. Alternatively to theevacuation of the interior of the cartridge 6 by means of a singlestroke of the vacuum plunger 30, the interior of the cartridge 6 canalso be evacuated by means of a number of strokes of the vacuum plunger30 by repeated operation of the lever 4 (pivoting of the lever 4 to andfro). For this purpose, the pump plunger 31 preferably can no longer bemoved in the direction of the check valves 27, 28 or least cannot bemoved into the pressure pump chamber 36 beyond the mouth of the funnel68. This can be achieved by way of example in that the pump plunger 31is releasably connected to the cable 34 or the rod 34 (see FIG. 6) sothat the pump plunger 34, after first-time operation, remains in an endposition bearing against the closure 33. Here, the pump plunger 31 canpreferably cover the mouth 25 in the fluid connection 70 in apressure-tight manner. The vacuum pump 3 can then be used for furtherevacuation of the interior of the cartridge 6, as the bone cement dough96 is being mixed by means of the mixing device 10. With a continuedmovement of the lever 4, the vacuum plunger 30 is thus moved back andforth via the cable 34 or the rod 34, whilst the cable 34 or the rod 34slides or passes through the closure 33 and the pump plunger 31 bearingagainst the closure.

The part of the interior of the hollow cylinder 29 between the frontclosure with the check valves 27, 28 thereon (on the left in FIGS. 3, 4and 7 to 9, on the right in FIG. 5, and at the top in FIG. 6) and thevacuum plunger 30 forms the vacuum pump chamber 94. A negative pressurein the vacuum pump chamber 94 can thus act through the vacuum line 26into the interior of the cartridge 6, or a gas can be evacuated from theinterior of the cartridge 6 when the sealing plunger 20, as shown in theFigures, is connected to the sterilisation plunger 22 and the interiorof the cartridge 6 is thus sealed externally, apart from the opening tothe vacuum line 26.

At the same time as the continued movement of the vacuum plunger 30, thecylinder 76 in the sleeve 80 is moved in the longitudinal direction viathe cable 86, 90 or the rod 86, 90 and the ball joint 84, and, in sodoing, is rotated via the threads 72, 82. The movement in thelongitudinal direction and the rotation is transferred via the mixingshaft 12 or the cable 12 through the feedthrough onto the mixing device10 in the interior of the cartridge 6. As a result of multiple pivotingof the lever 4 in both directions and thus movement of the mixing device10 in the interior of the cartridge 6, the content, specifically thebone cement powder 9 and the sucked-in monomer liquid, is mixed, therebyproducing a bone cement dough 96 in the interior of the cartridge 6.

When the starting components have been mixed in the interior of thecartridge 6 by means of the mixing blades 10, the cartridge system 1 isunscrewed from the housing 19 or the external thread 16 of the housing19, and the cable 12 or the mixing shaft 12 comprising the mixing device10 is removed from the interior of the cartridge 6. In so doing, themixing blades 10 collapse upwardly. For this purpose, tapered materialportions as predetermined bending points are provided at the point ofconnection of the mixing blades 10 to the mixing shaft 12.

The sealing plunger 20 is rotated relative to the sterilisation plunger22, and the gas feedthrough is thus closed by the sealing plunger 20.The vacuum line 26 is removed from the sealing plunger 20. Once thecartridge system 1 has been unscrewed, a dispensing pipe (not shown)having a matching external thread is screwed into the internal thread14, and the mixed bone cement 96 can be applied through said pipe. Theconveying plunger 8 or dispensing plunger 8 assembled from thesterilisation plunger 22 and the sealing plunger 20 is unlatched and canbe driven inside the cartridge 6 by means of an application device (notshown). The content in the cartridge 6, i.e. the bone cement dough 96mixed under negative pressure, is thus pressed out from the oppositeopening and through the screwed-on dispensing pipe.

The components of the vacuum mixing device, apart from the glass ampoule54, the filters 64, 72, and the starting components of the bone cement,can be produced from plastics material by injection moulding. The fluidconnection 70 can consist of another plastics material. The connectionline 26 can be flexible so as to be able to be removed more easily fromthe sealing plunger 20.

The lines 26, 70 and the cables 34, 86, 90 or the forked rod 34, 86, 90are arranged in the housing 19 made of plastics material, which isfixedly connected to the base part 18, wherein the base part 18 has aflat base so that the vacuum mixing device can be placed on a flatsubstrate.

Instead of the glass ampoule 54 used with the exemplary embodimentdescribed, another monomer liquid container can also be used. By way ofexample, a film bag containing the monomer liquid can be used ascontainer for the monomer liquid in a modified receptacle. The film bagby way of example can be a plastics material bag coated with aluminiumwhich is chemically sufficiently resistant to the monomer liquid. In thealternative receptacle 2, a mandrel or better still a blade can beprovided, which is to be pushed and moved against the film bag by meansof the opening device 5 so that the film bag is pierced or slit open bymeans of the mandrel or the blade via the opening device 5, such thatthe monomer liquid then runs out from the film bag and is available inthe receptacle 2. The container for the monomer liquid can also befixedly integrated in the receptacle 2 and therefore in the vacuummixing device and can be opened towards the filter 64 and/or sieve 64 ortowards the pressure pump chamber 36 by means of the opening device 5.

The variant with glass ampoule 54 as container for the monomer liquid ispreferred, however, in accordance with the invention, since the glassampoules 54 filled with monomer liquid are commercially availableinexpensively and in addition glass ampoules 54 are particularly wellsuited for long-term storage of the monomer liquid. Here, it isparticularly preferred for the glass ampoule 54 to be contained alreadyin the receptacle 2 of the vacuum mixing device.

Instead of a combined pressure-vacuum pump 3, as shown with theexemplary embodiment according to FIGS. 1 to 9, a pressure pump and avacuum pump separate from the pressure pump without a common hollowcylinder can also be used in a vacuum mixing device according to theinvention. Both the pressure pump and the vacuum pump then each have, byway of example, their own hollow cylinder and are each connected viatheir own cable or their own rod to a detent means or to the rod 90 orthe cable 90. The cable 90 or the rod 90 then for this purpose splits,instead of into two, into three cables or rods, one for the pressurepump, one for the vacuum pump, and one for the drive of the mixingdevice or for the mixing device directly.

With the described vacuum mixing device, the two starting components ofthe bone cement can be stored and mixed at any later moment in timeunder vacuum. Here, the vacuum mixing device does not have to beconnected to an external supply (power, water or compressed gas). Thereis no need for an internal energy store, such as a battery, a compressedgas cartridge or a tension spring, for driving the vacuum mixing deviceor the vacuum pump 3, the pressure pump 3, the mixing device 10, and theopening device 5. The energy necessary to generate the negative pressureis also applied manually, such as the force necessary to open the glassampoule 54 and the force necessary to move the mixing device 10.

The features of the invention disclosed in the above description and inthe claims, Figures and exemplary embodiments can be essential, bothindividually and in any combination, for the implementation of theinvention in its various embodiments.

LIST OF REFERENCE SIGNS

-   1 cartridge system-   2 receptacle-   3 combined pressure-vacuum pump-   4 operating element/lever-   5 opening device-   6 cartridge/cartridge wall/hollow cylinder-   8 dispensing plunger-   9 cement powder-   10 mixing device/mixing blades-   12 mixing shaft/cable-   14 internal thread-   16 external thread-   18 base part/stand-   19 housing-   20 sealing plunger-   22 sterilisation plunger-   24 pore plate-   25 mouth-   26 connection line/vacuum line-   27 check valve-   28 check valve/exhaust air-   29 hollow cylinder-   30 vacuum plunger-   31 pump plunger-   32 seal/O-ring-   33 closure-   34 cable/flexible rod-   35 pipe/rod/connection-   36 pressure pump chamber-   37 detent means-   38 mating detent means-   40 axis-   41 lever arm-   42 lever arm-   43 handle-   46 lever-   47 axis-   48 edge-   50 resilient insert-   52 hollow cylinder-   54 glass ampoule with monomer liquid-   56 ampoule head-   58 ampoule base-   60 support/shoulder-   62 hollow cylinder-   64 filter/sieve-   66 gap-   68 funnel-   70 fluid connection/liquid line-   72 powder-impermeable and liquid-permeable filter-   73 annular channel-   74 pin/deflection roller-   76 cylinder-   78 external thread/lobe-   80 sleeve-   82 internal thread-   83 involute-   84 ball-joint head-   86 cable/flexible rod-   88 pin/deflection roller-   90 cable/flexible rod-   91 ball-   92 spring-   94 vacuum pump chamber-   96 bone cement dough

We claim:
 1. A vacuum mixing device for mixing polymethylmethacrylatebone cement from a monomer liquid and a cement powder, the vacuum mixingdevice comprising: at least one cartridge having an evacuable interiorfor mixing of the bone cement, a mixing device for mixing the content inthe interior of the at least one cartridge, which is arranged movably inthe interior, a receptacle for receiving a separate container containingthe monomer liquid or comprising an integrated container containing themonomer liquid, an opening device, which is arranged in the region ofthe receptacle in a manner movable relative to the receptacle so that,by moving the opening device, a separate container arranged in thereceptacle is openable by means of the opening device, or the openingdevice is arranged in the region of the integrated container in a mannermovable relative to the integrated container so that, by moving theopening device, the integrated container is openable by means of theopening device, a vacuum pump, in which a movable vacuum plunger forgenerating a negative pressure is arranged and delimits a vacuum pumpchamber of the vacuum pump, a pressure pump, in which a movable pumpplunger for conveying a liquid is arranged and delimits a pressure pumpchamber of the pressure pump, a connection line, which connects theinterior of the at least one cartridge to the vacuum pump chamber of thevacuum pump, and a fluid connection, which connects the interior of theat least one cartridge to the pressure pump chamber of the pressurepump, wherein the vacuum mixing system comprises an operating elementthat is operatable from outside, wherein the vacuum plunger in thevacuum pump is movable manually by means of the operating element, thepump plunger in the pressure pump is movable manually by means of thesame operating element, the opening device is movable relative to thereceptacle or relative to the integrated container by means of the sameoperating element, and herein the mixing device in the interior of thecartridge is movable by means of the same operating element in order tomix the content in the interior of the cartridge.
 2. The vacuum mixingdevice according to claim 1, wherein the operating element is connectedor connectable to the vacuum plunger and to the pump plunger in such away that the vacuum plunger is movable manually in the vacuum pump andthe pump plunger is movable manually in the pressure pump by operationof the operating element.
 3. The vacuum mixing device according to claim1, wherein the receptacle, at least in regions, has closed side wallsfor receiving a glass ampoule as separate container, wherein thereceptacle has at least one deformable closed side wall and a supportingelement is provided opposite the deformable side wall, wherein theopening device is pressable via the operating element against thedeformable side wall of the receptacle so that the deformable side walldeforms in such a way that a matching glass ampoule arranged in thereceptacle can be broken open by means of the opening device.
 4. Thevacuum mixing device according to claim 1, wherein the opening devicehas a first lever which is mounted rotatably about a first axis inrelation to the receptacle or the integrated container, wherein a freeend of the first lever is pushable against a deformable side wall of thereceptacle or the integrated container, wherein the operating element isformed by a second lever, which is mounted rotatably about a second axisin relation to the receptacle or the integrated container, wherein thesecond axis divides the second lever into a short lever arm and a longlever arm, wherein an end of the short lever arm is to be pushed bymanual operation of the long lever arm against the first lever so thatthe free end of the first lever pushes against the deformable side walland deforms this in such a way that a separate container disposed in thereceptacle is openable, or pushes the free end of the first leveragainst the integrated container so that the integrated container openstowards a fluid connection.
 5. The vacuum mixing device according toclaim 1, wherein the operating element is manually movable, wherein theoperating element is operatively connected to or is to be brought intooperative connection with the opening device, the vacuum pump, thepressure pump, and the mixing device in such a way that with a firstoperation of the operating element a separate container in thereceptacle or the integrated container is to be opened, and with afurther operation of the operating element the vacuum plunger in thevacuum pump is to be driven, the pump plunger in the pressure pump is tobe driven, and the mixing device in the interior is to be driven.
 6. Thevacuum mixing device according to claim 5, wherein the vacuum plungerofthe vacuum pump, the pump plunger of the pressure pump and/or the mixingdevice are/is to be driven via a flexible cable and/or a rod, wherein adetent means is provided on the flexible cable and/or the rod and afterfirst-time operation of the operating element engages with a matingdetent means on the operating element or with a mating detent meansconnected to the operating element so that, with operation of theoperating element subsequent to the latching, the vacuum plunger of thevacuum pump, the pump plunger of the pressure pump and/or the mixingdevice are/is to be driven via the cable and/or the rod by means of theoperating element.
 7. The vacuum mixing device according to claim 1,wherein the mixing device is axially movable in the interior in thelongitudinal direction by operation of the operating element.
 8. Thevacuum mixing device according to claim 1, wherein the mixing device isrotatable about the longitudinal axis of the interior by operation ofthe operating element, wherein a cylinder connected to the mixing deviceand having an external thread moves in a stationary sleeve having amatching internal thread so that, when the cylinder moves along thelongitudinal direction within the sleeve, a rotation of the cylinder isenforced, wherein the rotation of the cylinder transfers to the mixingdevice in the interior of the cartridge.
 9. The vacuum mixing deviceaccording to claim 1, wherein the vacuum pump chamber of the vacuum pumpis gas-tight and is arranged in the interior of the vacuum pump, whereinthe vacuum plunger is manually drivable via the operating element in atleast one direction, such that the vacuum pump chamber is to be enlargedby the movement of the vacuum plunger and the interior of the at leastone cartridge is to be evacuable through the connection line by means ofthe resultant negative pressure created in the vacuum pump chamber. 10.The vacuum mixing device according to claim 1, wherein the pressure pumpchamber of the pressure pump is liquid-tight and is arranged inside thepressure pump, wherein the pump plunger is manually drivable via theoperating element in at least one direction so that the pressure pumpchamber is to be made smaller by the movement of the pump plunger andthe monomer liquid is to be pushed from the pressure pump chamberthrough the fluid connection into the interior of the at least onecartridge by means of the resultant pressure created in the pressurepump chamber.
 11. The vacuum mixing device according to claim 1, whereina first one-way valve is arranged in the connection from the vacuum pumpchamber to the connection line or in the connection line, which firstone-way valve is open or is actively opened when a pressure lower thanin the interior of the cartridge prevails in the vacuum pump chamber andis in a closed state or is actively closed when a pressure equal to orhigher than in the interior of the cartridge prevails in the vacuum pumpchamber, and a second one-way valve connects the vacuum pump chamber tothe surroundings of the vacuum pump, which second one-way valve is openor is actively opened when a pressure higher than in the surroundings ofthe vacuum pump prevails in the vacuum pump chamber and is in the closedstate or is actively closed when a pressure equal to or lower than inthe surroundings of the vacuum pump prevails in the vacuum pump chamber.12. The vacuum mixing device according to claim 1, wherein the vacuumplunger and the pump plunger are mounted axially movably in a hollowcylinder, wherein the hollow cylinder is closed on a first side or isclosed apart from a feedthrough for a rod or cable connected to theoperating element and the vacuum plunger and pump plunger, in particularis closed by a closure, wherein a vacuum pump chamber is formed in thehollow cylinder between the vacuum plunger and the first closed side,and a pressure pump chamber is formed in the hollow cylinder between thepump plunger and a closure, wherein the closure of the hollow cylinderis arranged on the side of the hollow cylinder opposite the first side.13. The vacuum mixing device according to claim 1, wherein the vacuumplunger and/or the pump plunger are/is connected or connectable to theoperating element via a rod and/or a cable, and the vacuum plunger is tobe moved in the vacuum pump by operation of the operating element and/orthe pump plunger is to be moved in the pressure pump by operation of theoperating element.
 14. The vacuum mixing device according to claim 1,wherein a movable dispensing plunger for discharging the mixed bonecement from the cartridge is arranged in the interior of the cartridge,wherein the dispensing plunger is releasably locked or lockable in orderto prevent a movement of the dispensing plunger under the action of thenegative pressure.
 15. The vacuum mixing device according to claim 1,wherein the cartridge is a cement cartridge filled with cement powderand a separate container containing a monomer liquid is arranged in thereceptacle or a monomer liquid is contained in the integrated container,wherein the receptacle or the integrated container is connected in aliquid-impermeable manner to the interior of the cement cartridge bymeans of a separating element that is openable and/or the interior ofthe cement cartridge is connected or connectable in a gas-permeablemanner to the vacuum pump.
 16. The vacuum mixing device according toclaim 1, wherein the cartridge, the vacuum pump, the pressure pump andall lines and also the receptacle or the integrated container arefixedly and/or releasably connected to a common base part and/or ahousing, wherein the vacuum pump, the pressure pump and all lines aswell as the receptacle or the separate container are fixedly connectedto the base part and/or a housing and the cartridge is releasablyconnected to the base part and/or a housing.
 17. The vacuum mixingdevice according to claim 1, wherein the separate container containingthe monomer liquid is a film bag which can be cut open or torn open inthe receptacle by means of the opening device, or is a glass ampoulewhich can be broken open in the receptacle by means of the openingdevice.
 18. The vacuum mixing device according to claim 1, wherein thereceptacle or the integrated container is connected or connectable via afluid connection to the interior of the cartridge, wherein the mouth ofthe fluid connection into the interior of the cartridge is arranged onthe opposite side of the mouth of the connection line between theinterior and the vacuum pump chamber.
 19. The vacuum mixing deviceaccording to claim 1, wherein a negative pressure is to be generated inthe vacuum pump chamber as a result of the movement of the vacuumplunger in the vacuum pump, wherein a gas is evacuable through theconnection line from the interior of the at least one cartridge by meansof the negative pressure.
 20. The vacuum mixing device according toclaim 1, wherein the vacuum pump and the pressure pump are constructedas a combined pressure-vacuum pump, the pressure-vacuum pump comprisinga hollow cylinder with a gas-tight closure at a first hollow cylinderend and a liquid-tight closure at the opposite second hollow cylinderend, wherein the hollow cylinder is connected or connectable at thefirst and at the second hollow cylinder end to the interior of thecartridge, the vacuum plunger, which is arranged in the hollow cylinderin a gas-tight and axially movable manner, and the pump plunger, whichis arranged in the hollow cylinder in a liquid-tight and axially movablemanner, wherein the vacuum plunger and the pump plunger in thepressure-vacuum pump are movable by means of the manually operableoperating element, wherein with a movement of the vacuum plunger bymeans of the manually operable operating element, the vacuum plunger ismovable axially away from the gas-tight closure and gas can thus beevacuated from the interior of the cartridge (6), and, when the pumpplunger is moved by means of the manually operable operating element,the pump plunger is movable axially towards the liquid-tight closure anda monomer liquid can thus be pushed from the pump chamber into theinterior of the cartridge, wherein the operating element is operativelyconnected to the opening device, and wherein the operating element isconnected to the mixing device in the interior of the cartridge in sucha way that the mixing device in the interior of the cartridge is movablewith operation of the operating element.
 21. The vacuum mixing deviceaccording to claim 1, characterised in that the vacuum pump, thepressure pump, the opening device, and the mixing device are drivablevia the movement of the operating element, wherein the operating elementis moved by the action of manual force.
 22. The vacuum mixing deviceaccording to claim 1, wherein the vacuum pump and the pressure pump areembodied as a combined pressure-vacuum pump, wherein the vacuum plungerand pump plunger are distanced from one another via a connection. 23.The vacuum mixing device according to claim 22, wherein the distancebetween the sides of the vacuum plunger and the pump plunger facing awayfrom one another is at least exactly the same as the maximum stroke ofthe vacuum plunger and the pump plunge.
 24. The vacuum mixing deviceaccording to claim 1, wherein the pump plunger is movable only in onedirection in order to reduce the size of the pressure pump chamber andthen cannot be moved back in the opposite direction, and is movable bythe connection only in a direction for reducing the size of the pressurepump chamber.
 25. A method for mixing polymethylmethacrylate bone cementin an interior of a cartridge of the vacuum mixing device, according toclaim 1, the method comprising: operating an operating element such thatan integrated container of the vacuum mixing device or a separatecontainer, which is arranged in a receptacle of the vacuum mixingdevice, is thus opened, wherein a monomer liquid contained in theintegrated container or the separate container then flows as firstcomponent of the bone cement into a pressure pump chamber of a pressurepump, by means of a subsequent, further operation of the operatingelement, a movement of a vacuum plunger of a vacuum pump of the vacuummixing device is driven, wherein a negative pressure is generated in avacuum pump chamber of the vacuum pump by means of the movement of thevacuum plunger, wherein the interior of the cartridge is evacuated bymeans of the vacuum pump driven in this way, a movement of a pumpplunger of a pressure pump of the vacuum mixing device is driven by thefurther operation of the operating element, wherein a pressure isexerted onto the monomer liquid in the pressure pump chamber by means ofthe movement of the pump plunger and the monomer liquid is pushed fromthe pressure pump chamber into the interior of the cartridge, wherein abone cement powder as second component of the bone cement is alreadydisposed in the interior of the cartridge, and a mixing device in theinterior of the cartridge is moved as a result of the operation of theoperating element and a bone cement dough in the interior of thecartridge formed from the cement powder and the monomer liquid is mixedas a result of the movement of the mixing device.
 26. The methodaccording to claim 25, where the volume of a vacuum pump chamber of thevacuum pump is increased by the manual movement of the vacuum plungerand the interior of the cartridge is evacuated due to the negativepressure created as a result and/or the volume of the pressure pumpchamber of the pressure pump is made smaller by the manual movement ofthe pump plunger and the monomer liquid is pushed from the pressure pumpchamber into the interior of the cartridge due to the pressure createdas a result.
 27. The method according to claim 25, wherein the vacuumplunger of the vacuum pump is moved, whereby a negative pressurerelative to the surrounding atmosphere is generated in the vacuum pump,in so doing gas from the interior of the cartridge is sucked into thevacuum pump chamber of the vacuum pump through a connection line, andthe pump plunger of the pressure pump is moved by means of the operatingelement, whereby a pressure is exerted onto the monomer liquid in thepressure pump chamber, the monomer liquid is pushed through a fluidconnection from the pressure pump chamber into the interior of thecartridge, the mixing device in the interior of the cartridge is thenmoved by operation of the same operating element, and in so doing thecement powder is mixed with the monomer liquid, the cartridge containingthe mixed cement dough is then removed, and the cement dough is pressedout from the cartridge by means of an axial movement of a dispensingplunger.
 28. The method according to claim 25, wherein the cement powderis arranged in the cartridge, the monomer liquid is arranged in areceptacle separate from the cartridge, wherein the monomer liquid iscontained in an integrated container or in a separate container, theintegrated container or the separate container is opened by operation ofthe operating element and a resultant movement of the opening device,before the vacuum plunger and the pump plunger are driven by a furtheroperation of the operating element, the vacuum plunger and the pumpplunger are then moved axially in a hollow cylinder, in so doing gasfrom the interior of the cartridge is sucked through the connection lineinto the vacuum pump chamber delimited by the hollow cylinder, and themonomer liquid disposed in the pressure pump chamber delimited by thehollow cylinder is pushed through the fluid connection into the interiorof the cartridge.